Messages in this thread | | | Subject | Re: [PATCH] device core: fix dma_mask handling in platform_device_register_full | From | Robin Murphy <> | Date | Wed, 11 Mar 2020 16:19:01 +0000 |
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On 11/03/2020 4:07 pm, Christoph Hellwig wrote: > Ever since the generic platform device code started allocating DMA masks > itself the code to allocate and leak a private DMA mask in > platform_device_register_full has been superflous. More so the fact that > it unconditionally frees the DMA mask allocation in the failure path > can lead to slab corruption if the function fails later on for a device > where it didn't allocate the mask. Just remove the offending code.
I'm sure I mentioned this in passing at the time, but only in the context of a cleanup; I never noticed it could be cause for an actual bug :)
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> Fixes: cdfee5623290 ("driver core: initialize a default DMA mask for platform device") > Reported-by: Artem S. Tashkinov <aros@gmx.com> > Tested-by: Artem S. Tashkinov <aros@gmx.com> > --- > drivers/base/platform.c | 14 -------------- > 1 file changed, 14 deletions(-) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index 7fa654f1288b..47d3e6187a1c 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -662,19 +662,6 @@ struct platform_device *platform_device_register_full( > pdev->dev.of_node_reused = pdevinfo->of_node_reused; > > if (pdevinfo->dma_mask) { > - /* > - * This memory isn't freed when the device is put, > - * I don't have a nice idea for that though. Conceptually > - * dma_mask in struct device should not be a pointer. > - * See http://thread.gmane.org/gmane.linux.kernel.pci/9081 > - */ > - pdev->dev.dma_mask = > - kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL); > - if (!pdev->dev.dma_mask) > - goto err; > - > - kmemleak_ignore(pdev->dev.dma_mask); > - > *pdev->dev.dma_mask = pdevinfo->dma_mask; > pdev->dev.coherent_dma_mask = pdevinfo->dma_mask; > } > @@ -700,7 +687,6 @@ struct platform_device *platform_device_register_full( > if (ret) { > err: > ACPI_COMPANION_SET(&pdev->dev, NULL); > - kfree(pdev->dev.dma_mask); > platform_device_put(pdev); > return ERR_PTR(ret); > } >
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